Chitosano

Chitosano, known in English as chitosan, is a natural polysaccharide derived from chitin through deacetylation. It is obtained primarily from the shells of crustaceans such as shrimp, crab, and lobster, though fungal sources are also used. The polymer is composed of repeating units of D-glucosamine and N-acetyl-D-glucosamine and possesses free amino groups that confer a positive charge in acidic solutions.

Chitosano's solubility and properties depend on the degree of deacetylation and molecular weight. It is soluble in dilute acids, forms viscous solutions, and can be processed into films, beads, fibers, and hydrogels. It is biocompatible and biodegradable, and exhibits chelating, adhesive, and antimicrobial properties under certain conditions. The material can be crosslinked to adjust mechanical strength and degradation rate.

Applications include biomedical uses such as drug delivery systems, wound dressings, and tissue engineering scaffolds; water treatment for removal of anionic pollutants and heavy metals; agriculture as a seed coating and plant growth enhancer; and food packaging or edible films to improve shelf life.

Safety and regulation: chitosano is generally regarded as safe for many applications, but regulatory status varies by country and by intended use. Allergic reactions related to shellfish are typically a concern only if residues remain; medical-grade chitosan products require appropriate testing and approvals.